<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="https://unpkg.com/vue@next"></script>
</head>
<body>
<div id="app" class="demo" ></div>

</body>
<script>
    const app=Vue.createApp({
        data(){
            return{count:4}
        },
        methods:{
            increment(){
                this.count++
            }
        }
    })

    const vm =app.mount('#app')
    document.write(vm.count)
    vm.increment()
    document.write(vm.count)



</script>
</html>